An additional puzzle: why doesn't this work?

if ( ref($self) eq 'person') { $self->tellName(); } if ( ref($self) eq
+ 'child') {$self->SUPER::tellName();}
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Because perl looks at the code $self->SUPER::tellName(), and says, ah, you want to call the tellName method in the superclass of the current package. It doesn't take $self into account at all. To do that, you need to go beyond what perl itself provides and use something like SUPER or NEXT.